Fentanyl

Mechanism of action

Opioid analgesic (strong).

Analgesic properties are based mostly on its selective agonism to the μ-opioid receptor (MOR) which is crucial for transmission of information about pain throughout the central nervous system. These receptors are located mostly in brainstem and thalamus.

Indications and dose

Pharmacokinetics

Onset of action: 5 minutes (IV)

Duration of action: 1–2 hours

Half-life of elimination: 3 hours

Metabolism: Hepatic (CYP450 3A4)

Elimination: Kidneys (90 %), liver (10 %)

Directions for administration

Lowest effective dose for shortest time possible is recommended.

Is 100x stronger than morphine: 100 μg fentanyl ~ 10 mg morphine

Side-effects

Acute:

Drowsiness

Respiratory depression

Nausea, vomiting

Dysphoria

Delirium

Seizures

Bradycardia

Hypotension

Urinary retention

Constipation

Urticaria

Pruritus

Chronic:

Tolerance, addiction

Withdrawal effects

Hyperalgesia

Hypogonadism

Immunosuppression

Medicinal forms

Many medicinal forms:
Solution for Injection/Infusion (50 μg/ml; 1 vial = 2 ml)
Sublingual tablets, Lozenges, Transdermal patch. Nasal spray.

Reversal

Rapid reversal may be achieved with Naloxone.

See more about it in the Naloxone list.

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References

1. Fentanyl: Uses, Interactions, Mechanism of Action | DrugBank Online
2. https://www.medicines.org.uk/emc/search?q=fentanyl
3. Pharm 101: Fentanyl • LITFL • Top 200 Drugs
4. Fentanyl - an overview | ScienceDirect Topics
5. Comparison between intravenous morphine versus fentanyl in acute pain relief in drug abusers with acute limb traumatic injury - PMC (nih.gov)